The Morphology/Ultrastructure Core Laboratory provides access to instrumentation, technical assistance, instruction, and consultation for SCOR investigators conducting cell biological and morphologic studies at the histologic and ultrastructural level. This centralized laboratory maintains access to a full range of light and electron microscopes, ancillary apparatus and preparative resources, computer assisted image, morphometric, and densitometric analysis, and a complete photographic facility. The laboratory is staffed by well qualified, experienced technicians under the direction of the Principal Investigator. Five proposed projects will rely extensively on the resources available in this unit and all projects will require periodic access to the photographic facility. The wide range of instrumentation and the cost effectiveness with which the laboratory is able to operate is directly attributable to shared support with other research units which also use the facility as a core laboratory.